Autoinjector triggered by skin contact

ABSTRACT

An autoinjector includes a case adapted to hold a medicament container having a needle telescopically coupled to the case and movable between a first extended position relative to the case in which the needle is covered and a retracted position relative to the case in which the needle is exposed. The autoinjector includes a plunger rotationally and slidably disposed in the case rotatable relative to the case between a first rotational position in which the plunger is engaged to the case and a second rotational position in which the plunger disengages the case engages the plunger to rotate the plunger from the first rotational position to the second rotational position when the needle shroud translates from the first extended position to the retracted position. The autoinjector includes a cap removably coupled to the case includes at least one compliant case beam adapted to releasably engage at least one aperture in the case.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. national stage application under 35 USC § 371 of International Application No. PCT/EP2015/056686, filed on Mar. 27, 2015, which claims priority to European Patent Application No. 14162454.4, filed on Mar. 28, 2014, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

This disclosure relates to an autoinjector.

BACKGROUND

Administering an injection is a process which presents a number of risks and challenges for users and healthcare professionals, both mental and physical. Injection devices typically fall into two categories—manual devices and autoinjectors. In a conventional manual device, manual force is required to drive a medicament through a needle. This is typically done by some form of button/plunger that has to be continuously pressed during the injection. There are numerous disadvantages associated with this approach. For example, if the button/plunger is released prematurely, the injection will stop and may not deliver an intended dose. Further, the force required to push the button/plunger may be too high (e.g., if the user is elderly or a child). And, aligning the injection device, administering the injection and keeping the injection device still during the injection may require dexterity which some patients (e.g., elderly patients, children, arthritic patients, etc.) may not have.

Autoinjector devices aim to make self-injection easier for patients. A conventional autoinjector may provide the force for administering the injection by a spring, and trigger button or other mechanism may be used to activate the injection. Autoinjectors may be single-use or reusable devices.

There remains a need for an improved autoinjector.

SUMMARY

Certain aspects of the present invention provide an improved autoinjector.

In an exemplary embodiment an autoinjector according to one aspect of the invention comprises:

-   -   a case adapted to hold a medicament container having a needle;     -   a needle shroud telescopically coupled to the case and movable         between a first extended position relative to the case in which         the needle is covered and a retracted position relative to the         case in which the needle is exposed; and     -   a plunger rotationally and slidably disposed in the case, the         plunger rotatable relative to the case between a first         rotational position in which the plunger is engaged to the case         and a second rotational position in which the plunger disengages         the case,     -   wherein the needle shroud engages the plunger to rotate the         plunger from the first rotational position to the second         rotational position when the needle shroud translates from the         first extended position to the retracted position, the         auto-injector further comprising:     -   a cap removably coupled to the case, wherein the cap includes at         least one compliant case beam adapted to releasably engage at         least one aperture in the case.

In an exemplary embodiment, when the cap is moved in the distal direction relative to the case, the at least one compliant beam disengages the at least one aperture in the case and no longer radially abuts the case.

In an exemplary embodiment the needle shroud is movable to a second extended position relative to the case in which the needle is covered and the needle shroud cannot translate relative to the case.

In an exemplary embodiment the cap includes an element adapted to engage a protective needle sheath removably disposed on the needle.

In an exemplary embodiment the cap includes at least one compliant beam adapted to releasably engage at least one radial aperture in the needle shroud.

In an exemplary embodiment, when the cap is coupled to the case, the at least one compliant beam engages the at least one radial aperture in the needle shroud and radially abuts the case.

In an exemplary embodiment, when the cap is removed from the case, the at least one compliant beam disengages the at least one radial aperture in the needle shroud and no longer radially abuts the case.

In an exemplary embodiment the autoinjector further comprises a shroud spring biasing the needle shroud in a distal direction relative to the case.

In an exemplary embodiment a force required to disengage the at least one compliant case beam from the respective aperture is greater than a force exerted by the shroud spring when the compliant case beam is engaged in the aperture.

In an exemplary embodiment the autoinjector further comprises a drive spring biasing the plunger in a distal direction relative to the case.

In an exemplary embodiment the plunger translates relative to the case under force of the drive spring when the plunger is in the second rotational position and the needle shroud is in the retracted position.

In an exemplary embodiment the plunger is at least partially hollow and the drive spring is at least partially disposed within the plunger.

In an exemplary embodiment the needle shroud includes at least one compliant shroud beam radially abutting the case when the needle shroud is in the first extended position and the retracted position, wherein the at least one compliant shroud beam deflects radially when the needle shroud is in the second extended position and axially abuts the case.

In an exemplary embodiment the plunger includes a first plunger boss adapted to engage a shroud rib disposed on the needle shroud and a second plunger boss adapted to engage a case slot in the case.

In an exemplary embodiment, when the plunger is in the first rotational position and the needle shroud is in the first extended position, the first plunger boss engages the shroud rib and the second plunger boss engages the case slot.

In an exemplary embodiment, when the needle shroud is in the retracted position, the plunger rotates from the first rotational position to a second rotational position and disengages the case slot.

In an exemplary embodiment the plunger includes a plunger boss adapted to engage a case slot in the case, and a plunger rib adapted to engage a shroud rib disposed on the needle shroud.

In an exemplary embodiment, when the plunger is in the first rotational position and the needle shroud is in the first extended position, the plunger boss engages the case slot.

In an exemplary embodiment, when the needle shroud translates from the first extended position to the retracted position, the needle shroud abuts the plunger rib to rotate the plunger relative to the case from the first rotational position to a second rotational position to disengage the plunger boss from the case slot.

In an exemplary embodiment, the cap comprises:

-   -   a distal face;     -   at least one compliant sheath removal beam extending in a         proximal direction from the distal face and defining a space for         receiving the protective needle sheath, the at least one         compliant sheath removal beam including at least one ledge         adapted to engage the protective needle sheath,     -   wherein the at least one compliant sheath removal beam is         disposed approximately perpendicular to the distal face in a         first position for engaging the protective needle sheath and is         disposed at a non-approximately perpendicular angle to the         distal face in a second position for receiving the protective         needle sheath.

The cap is suitable for being applied with any kind of injection device or autoinjector.

In an exemplary embodiment the at least one compliant sheath removal beam is biased toward the first position.

In an exemplary embodiment the ledge is adapted to engage proximally behind a proximal end of the protective needle sheath or into a recess within the protective needle sheath.

In an exemplary embodiment the cap further comprises one or more lateral apertures arranged in distal face of the cap or in a lateral area of the cap to allow insertion of at least one assembling tool for applying a force to move the at least one compliant sheath removal beam from the first position to the second position.

The sheath removal mechanism allows for engaging the protective needle sheath during assembly. When the cap is removed from the case of the medicament delivery device in preparation of an injection the sheath removal mechanism pulls out the protective needle sheath reliably without exposing the user to too high a risk to injure themselves. The sheath removal mechanism is suited for removing a protective needle sheath even if the protective needle sheath is arranged far behind an orifice of the medicament delivery device making it impossible to be gripped manually. Thus the needle can be arranged in the case initially a distance back from the orifice in order to prevent the user from touching the tip of the needle after the protective needle sheath is removed.

Further scope of applicability of certain aspects of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating exemplary embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art form this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

Certain aspects of the present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein:

FIG. 1A is a longitudinal section of an exemplary embodiment of an autoinjector according to certain aspects of the present invention during assembly,

FIG. 1B is a schematic side view of an exemplary embodiment of an autoinjector according to certain aspects of the present invention during assembly,

FIG. 2 is a schematic view of an exemplary embodiment of a shroud lock mechanism of an exemplary embodiment of an autoinjector according to certain aspects of the present invention,

FIG. 3 is a perspective exploded view of an exemplary embodiment of a control subassembly of an exemplary embodiment of an autoinjector according to certain aspects of the present invention,

FIG. 4 is a perspective exploded view of an exemplary embodiment of a drive subassembly of an exemplary embodiment of an autoinjector according to certain aspects of the present invention,

FIG. 5 is a perspective view of an exemplary embodiment of a needle sheath removal mechanism of an exemplary embodiment of an autoinjector according to certain aspects of the present invention,

FIG. 6 is a schematic view of an exemplary embodiment of a plunger release mechanism of an exemplary embodiment of an autoinjector according to certain aspects of the present invention,

FIG. 7 is a schematic view of an exemplary embodiment of a plunger release mechanism of an exemplary embodiment of an autoinjector according to certain aspects of the present invention during assembly,

FIG. 8 is a schematic view of an exemplary embodiment of a plunger release mechanism of an exemplary embodiment of an autoinjector according to certain aspects of the present invention after assembly,

FIG. 9 is a schematic view of an exemplary embodiment of a shroud lock mechanism of an exemplary embodiment of an autoinjector according to certain aspects of the present invention after assembly,

FIG. 10 is a schematic view of an exemplary embodiment of shroud lock mechanism of an exemplary embodiment of an autoinjector according to certain aspects of the present invention during assembly,

FIG. 11 is a schematic view of an exemplary embodiment of shroud lock mechanism of an exemplary embodiment of an autoinjector according to certain aspects of the present invention during assembly,

FIG. 12 is a schematic view of an exemplary embodiment of shroud lock mechanism of an exemplary embodiment of an autoinjector according to certain aspects of the present invention during assembly,

FIG. 13 is a schematic view of an exemplary embodiment of shroud lock mechanism of an exemplary embodiment of an autoinjector according to certain aspects of the present invention during assembly,

FIG. 14 is a schematic view of an exemplary embodiment of shroud lock mechanism of an exemplary embodiment of an autoinjector according to certain aspects of the present invention after assembly,

FIG. 15A is a longitudinal section of an exemplary embodiment of an autoinjector according to certain aspects of the present invention after assembly,

FIG. 15B is a schematic side view of an exemplary embodiment of an autoinjector according to certain aspects of the present invention after assembly,

FIG. 16 is a schematic view of an exemplary embodiment of a shroud lock mechanism an exemplary embodiment of an autoinjector according to certain aspects of the present invention prior to use,

FIG. 17A is a longitudinal section of an exemplary embodiment of a shroud lock mechanism an exemplary embodiment of an autoinjector according to certain aspects of the present invention prior to use,

FIG. 17B is a schematic side view of an exemplary embodiment of a shroud lock mechanism an exemplary embodiment of an autoinjector according to certain aspects of the present invention prior to use,

FIG. 18A is a longitudinal section of an exemplary embodiment of an autoinjector according to certain aspects of the present invention during use,

FIG. 18B is a schematic side view of an exemplary embodiment of an autoinjector according to certain aspects of the present invention during use,

FIG. 19 is a schematic view of an exemplary embodiment of a plunger release mechanism of an exemplary embodiment of an autoinjector according to certain aspects of the present invention during use,

FIG. 20A is a longitudinal section of an exemplary embodiment of an autoinjector according to certain aspects of the present invention during use,

FIG. 20B is a schematic side view of an exemplary embodiment of an autoinjector according to certain aspects of the present invention during use,

FIG. 21A is a longitudinal section of an exemplary embodiment of an autoinjector according to certain aspects of the present invention after use,

FIG. 21B is a schematic side view of an exemplary embodiment of an autoinjector according to certain aspects of the present invention after use,

FIG. 22 is a schematic view of an exemplary embodiment of a shroud lock mechanism of an exemplary embodiment of an autoinjector according to certain aspects of the present invention after use,

FIGS. 23A-E is a schematic view of another exemplary embodiment of a plunger release mechanism before, during and after use,

FIGS. 24A-B are different schematic longitudinal sections of another exemplary embodiment of the autoinjector,

FIG. 25A is a schematic view of a distal end of an exemplary embodiment of an autoinjector according to certain aspects of the present invention during assembly,

FIG. 25 B is a schematic view of an exemplary embodiment of a cap to be attached to an auto-injector,

FIG. 26 is a schematic view of the distal end of the autoinjector with the assembled cap during insertion of a wedge shaped assembly tool through an aligned set of lateral apertures,

FIG. 27 is a schematic view of the distal end of the autoinjector with the assembled cap and the inserted assembly tool during assembly of a medicament container with a protective needle sheath, and

FIG. 28 is a schematic view of the distal end of the autoinjector with the assembled cap, medicament container and protective needle sheath.

Corresponding parts are marked with the same reference symbols in all figures.

DETAILED DESCRIPTION

FIG. 1A is a longitudinal section of an exemplary embodiment of an autoinjector 1 according to certain aspects of the present invention during assembly. The autoinjector 1 comprises a case 2 comprising a front case 2.1 and a rear case 2.2. The case 2 is adapted to hold a medicament container, such as a syringe 3. The syringe 3 may be a pre-filled syringe and have a needle 4 arranged at a distal end. When the autoinjector 1 and/or the syringe 3 are assembled, a protective needle sheath 5 may be removably coupled to the needle 4. The protective needle sheath 5 may be a rubber needle sheath or a rigid needle sheath (which is composed of rubber and a full or partial plastic shell). A stopper 6 is arranged for sealing the syringe 3 proximally and for displacing a medicament M contained in the syringe 3 through the needle 4. In other exemplary embodiments, the medicament container may be a cartridge which includes the medicament M and engages a removable needle (e.g., by threads, snaps, friction, etc.).

In an exemplary embodiment, a cap 11 may be removably disposed at a distal end of the case 2. The cap 11 may include an element (e.g., a barb, a hook, a narrowed section, etc.) arranged to engage the protective needle sheath 5, the case 2 and/or a needle shroud 7 telescoped within the case 2. The cap 11 may comprise grip features 11.5 for facilitating removal of the cap 11 (e.g., by twisting and/or pulling the cap 11.5 relative to the case 2).

In an exemplary embodiment, a shroud spring 8 is arranged to bias the needle shroud 7 in a distal direction D against the case 2.

In an exemplary embodiment, a drive spring 9 is arranged within the case 2. A plunger 10 serves for forwarding a force of the drive spring 9 to the stopper 6. In an exemplary embodiment, the plunger 10 is hollow and the drive spring 9 is arranged within the plunger 10 biasing the plunger 10 in the distal direction D against the case 2. In another exemplary embodiment, the plunger 10 may be solid and the drive spring 9 may engage a proximal end of the plunger 10. Likewise, the drive spring 9 could be wrapped around the outer diameter of the plunger 10 and extend within the syringe 3.

In an exemplary embodiment, a plunger release mechanism 12 is arranged for preventing release of the plunger 10 prior to retraction of the needle shroud 7 relative to the case 2 and for releasing the plunger 10 once the needle shroud 7 is sufficiently retracted.

In an exemplary embodiment, a first shroud lock mechanism 14 is arranged to prevent retraction of the needle shroud 7 relative to the case 2 when the cap 11 is in place, thereby avoiding unintentional activation of the autoinjector 1 (e.g., if dropped, during shipping or packaging, etc.). The first shroud lock mechanism 14 may comprise one or more compliant beams 11.3 on the cap 11 and a respective number of apertures 7.6 in the needle shroud 7 adapted to receive each of the compliant beams 11.3. When the cap 11 is attached to the autoinjector 1, the compliant beams 11.3 abut a radial stop 2.15 on the case 2 which prevents the compliant beams 11.3 from disengaging the apertures 7.6. When the cap 11 is attached to the autoinjector 1, axial movement of the cap 11 in the proximal direction P relative the case 2 is limited by a rib 11.4 on the cap 11 abutting the case 2. When the cap 11 is pulled in the distal direction D relative to the case 2, the compliant beams 11.3 may abut an edge of the aperture 7.6 and deflect to disengage the aperture 7.6, allowing for removal of the cap 11 and the protective needle sheath 5 attached thereto. In an exemplary embodiment, the compliant beams 11.3 and/or the apertures 7.6 may be ramped to reduce force necessary to disengage the compliant beams 11.3 from the apertures 7.6.

FIG. 1B is a schematic side view of an exemplary embodiment of the autoinjector 1 according to certain aspects of the present invention during assembly. In the exemplary embodiment in FIG. 1B, the case 2 is removed for clarity. FIG. 1B and FIG. 2 show a second shroud lock mechanism 15 that is adapted to lock the needle shroud 7 in an axial position relative to the case 2 after the autoinjector 1 has been removed from the injection site. In an exemplary embodiment, the second shroud lock mechanism 15 comprises at least one compliant shroud beam 7.1 on the needle shroud 7 adapted to proximally abut a stop 2.12 on the case 2 after the autoinjector 1 has been removed from the injection site. The abutment of the shroud beam 7.1 on the stop 2.12 prevents translation of the needle shroud 7 in the proximal direction P relative to the case 2. Prior to use, when the cap 11 is attached to the autoinjector 1, the cap 11 is adapted to engage and deflect the compliant shroud beam 7.1 radially inward, allowing the shroud beam 7.1 to pass the stop 2.12 in the proximal direction P so that the needle shroud 7 can translate in the proximal direction P relative to the case 2.

In an exemplary embodiment, the autoinjector 1 may formed from at least two subassemblies, e.g., a control subassembly 1.1 and a drive subassembly 1.2, to allow for flexibility as to the time and location of manufacture of the subassemblies 1.1, 1.2 and final assembly with the syringe 3.

FIG. 3 is a perspective exploded view of an exemplary embodiment of a control subassembly 1.1 of an autoinjector 1 according to certain aspects of the present invention. In an exemplary embodiment, the control subassembly 1.1 comprises the cap 11, the needle shroud 7, the shroud spring 8 and the front case 2.1. To assemble the control subassembly 1.1, the shroud spring 8 is inserted into the needle shroud 7, and the needle shroud 7 with the shroud spring 8 is inserted into the front case 2.1. The cap 11 is arranged over the distal end of the needle shroud 7.

FIG. 4 is a perspective exploded view of an exemplary embodiment of a drive subassembly 1.2 of an autoinjector 1 according to certain aspects of the present invention. In an exemplary embodiment, the drive subassembly 1.2 the plunger 10, the drive spring 9 and the rear case 2.2. Those of skill in the art will understand that if the viscosity or volume, for example, of the medicament M in the syringe 3 is changed, only parts of the drive subassembly 1.2 may need to be changed. To assemble the drive subassembly 1.2, the drive spring 9 is inserted into the plunger 10 and the plunger 10 is inserted in the rear case 2.2 in the proximal direction P thereby compressing the drive spring 9. Once the plunger 10 and the drive spring 9 reach a compressed position it is rotated by an angle, e.g. approximately 30° relative to the rear case 2.2, to engage the plunger 10 to the rear case 2.2. In an exemplary embodiment, the rear case 2.2 may have a cam surface to engage the plunger 10 to induce this rotation prior to the plunger 10 and the drive spring 9 reaching the compressed position.

FIG. 5 is a perspective view of an exemplary embodiment of a needle sheath removal mechanism 13 of an autoinjector 1 according to certain aspects of the present invention. The needle sheath removal mechanism 13 comprises an opening 11.1 axially arranged in the cap 11. The opening 11.1 is approximately sized and shaped to receive the protective needle sheath 5. One or more bosses 11.2 may be disposed on a proximal end of the cap 11 and adapted to abut the protective needle sheath 5. For example, when the protective needle sheath 5 is inserted into the opening 11.1, the protective needle sheath 5 may deform around the bosses 11.2. The bosses 11.2 may be ramped to reduce force necessary to insert the protective needle sheath 5 into the opening 11.1. Once the protective needle sheath 5 has passed the bosses 11.2 in the distal direction D, the bosses 11.2 may abut a proximal end of the protective needle sheath 5 to prevent translation of the protective needle sheath 5 in the proximal direction P relative to the cap 11. For example, during removal of the cap 11 from the autoinjector 1, the bosses 11.2 on the cap 11 may abut the proximal end of the protective needle sheath 5 and push the protective needle sheath 5 in the distal direction D off of the needle 4 with their non-ramped distal face. Those of skill in the art will understand that a number of parameters can be varied, e.g. a radial height of the boss 11.2, an axial length of the boss 11.2, an angle of the ramp of the boss 11.2, a durometer of the protective needle sheath 5, a surface finish of the boss 11.2, etc., which could increase or decrease assembly forces, cap removal forces, etc.

FIG. 6 is a schematic view of an exemplary embodiment of a plunger release mechanism 12 of the autoinjector 1 according to certain aspects of the present invention during assembly. The plunger release mechanism 12 is arranged for preventing release of the plunger 10 prior to retraction of the needle shroud 7 relative to the case 2 and for releasing the plunger 10 once the needle shroud 7 is sufficiently retracted. In an exemplary embodiment, the plunger release mechanism 12 comprises the plunger 10, the rear case 2.2, and the needle shroud 7 interacting with each other. In an exemplary embodiment, the needle shroud 7 is limited to axial movement relative to the case 2, and the plunger 10 can translate axially and rotate relative to the case 2.

In an exemplary embodiment, the plunger 10 comprises a first plunger boss 10.1 adapted to engage a shroud rib 7.7 on the needle shroud 7, a second plunger boss 10.2 adapted to engage a case slot 2.3 in the case 2, and a plunger rib 10.3 adapted to engage the shroud rib 7.7 on the needle shroud 7. In an exemplary embodiment, the shroud rib 7.7 comprises a proximal face 7.8 adapted to engage the plunger rib 10.3, and a distal face 7.9 and a longitudinal face 7.10 adapted to engage the first plunger boss 10.1. In an exemplary embodiment, the case slot 2.3 comprises a first angled surface 2.9 adapted to apply a rotational force in a first rotational direction R1 to the second plunger boss 10.2, a wall 2.10 adapted to abut the second plunger boss 10.2 to limit rotation of the plunger 10 relative to the case 2 in the first rotational direction R1, and a second angled surface 2.11 adapted to apply a rotational force in a second rotational direction R2, opposite the first rotational direction R1, to the second plunger boss 10.2.

In an exemplary embodiment of an assembly process of the drive subassembly 1.2, the plunger 10 with the drive spring 9 is inserted into the rear case 2.2. When the second plunger boss 10.2 is axially aligned with the case slot 2.3, the plunger 10 is rotated in the first rotational direction R1 until the second plunger boss 10.2 is moved into the case slot 2.3 until it abuts the wall 2.10. In this position, the first angled surface 2.9 prevents the second plunger boss 10.2 from moving in the second rotational direction R2, and thus prevents the plunger 10 from rotating relative to the case 2.

After a syringe 3 (with the protective needle sheath 5 disposed on the needle 4) is inserted into the control assembly 1.1, the drive subassembly 1.2 is coupled to the control subassembly 1.1. In an exemplary embodiment, a pair of resilient beams 2.13 (shown in FIG. 1B) on the rear case 2.2 is adapted to snap into recesses 2.14 (shown in FIG. 3) in the front case 2.1 to lock the drive subassembly 1.2 to the control subassembly 1.1. As the drive assembly 1.2 is coupled to the control subassembly 1.1, the needle shroud 7 translates proximally (e.g., by use of an assembly jig) causing the shroud rib 7.7 to abut the plunger rib 10.3. As shown in FIG. 7, as the shroud rib 7.7 pushes plunger rib 10.3, the angle of the plunger rib 10.3 causes the plunger 10 to rotate relative to the case 2 in the second rotational direction R2, and the second plunger boss 10.2 rides along the first angled surface 2.9 onto the second angled surface 2.11. When the second plunger boss 10.2 is disposed on the second angled surface 2.11, the force of the drive spring 9 imparts a rotational force on the plunger 10 in the second rotational direction R2 due to the angle of the second angled surface 2.11.

As shown in FIG. 8, when the needle shroud 7 is released (e.g., by removing the assembly jig), the needle shroud 7 translates in the distal direction D relative to the case 2 under the force the shroud spring 8 until the shroud rib 7.7 abuts the first plunger boss 10.1. For example, the distal face 7.9 of the shroud rib 7.7 may abut the first plunger boss 10.1 and maintain the needle shroud 7 in an axial position relative to the case 2. The second plunger boss 10.2 is prevented from disengaging the case slot 2.3, because the shroud rib 7.7 prevents the plunger 10 from rotating in the second rotational direction R2 relative to the case 2. For example, the longitudinal face 7.10 of the shroud rib 7.7 abuts the first plunger boss 10.1 to prevent rotation of the plunger 10.

FIG. 9 shows an exemplary embodiment of the first shroud lock mechanism 14 for an autoinjector 1 according to certain aspects of the present invention after assembly of the control subassembly 1.1. The compliant beam 11.3 on the cap is engaged in the aperture 7.6 within the needle shroud 7. The radial stop 2.15 is axially spaced from the compliant beam 11.3.

FIG. 10 shows an exemplary embodiment of the first shroud lock mechanism 14 for an autoinjector 1 according to certain aspects of the present invention during insertion of the syringe 3 into the control subassembly 1.1 for engaging the protective needle sheath 5 to the cap 11. The aperture 7.6 provides some clearance allowing a movement of the needle shroud 7 relative to the cap 11 in the distal direction D. The front case 2.1 is also moved in the distal direction D relative to the cap 11 axially aligning the radial stop 2.15 with the compliant beam 11.3 preventing the cap 11 from disengaging the needle shroud 7.

FIG. 11 shows an exemplary embodiment of the first shroud lock mechanism 14 for an autoinjector 1 according to certain aspects of the present invention, wherein after insertion of the syringe 3, the needle shroud 7 is moved further in the proximal direction P relative to the front case 2.1 by an assembly jig (not illustrated). In this state, the drive subassembly 1.2 may be assembled to the control subassembly 1.1. The compliant beam 11.3 remains engaged in the aperture 7.6 and the radial stop 2.15 prevents them from disengaging.

After assembly of the drive subassembly 1.2 to the control subassembly 1.1, the assembly jig is removed allowing the needle shroud 7 to move back in the distal direction D relative to the front case 2.1 under the force of the shroud spring 8 arriving again in the state illustrated in FIG. 10. In this configuration, the needle shroud 7 is prevented from moving in the proximal direction P relative to the case 2, because the radial stop 2.15 prevents the compliant beam 11.3 from disengaging the aperture 7.6 and the rib 11.4 on the cap 11 proximally abuts the front case 2.1.

FIG. 12 shows an exemplary embodiment of the second shroud lock mechanism 15 for an autoinjector 1 according to certain aspects of the present invention after assembly of the control subassembly 1.1. The needle shroud 7 is partially inserted into the cap 11. The shroud beam 7.1 is in a non-deflected position proximally abutting the stop 2.12 in the front case 2.1. This prevents the needle shroud 7 from moving further in the proximal direction P relative to the front case 2.1 and keeps the control subassembly 1.1 locked together.

FIG. 13 shows an exemplary embodiment of the second shroud lock mechanism 15 for an autoinjector 1 according to certain aspects of the present invention during insertion of the syringe 3 into the control subassembly 1.1, wherein the needle shroud 7 is moved further in the distal direction D into the cap 11 such that the cap 11 radially inwardly deflects the shroud beam 7.1 out of its abutment with the stop 2.12. The needle shroud 7 is thus free to move in the proximal direction P relative to the front case 2.1.

FIG. 14 shows an exemplary embodiment of the second shroud lock mechanism 15 for an autoinjector 1 according to certain aspects of the present invention after final assembly of the drive subassembly 1.2 to the control subassembly 1.1. The needle shroud 7 has been moved further in the proximal direction P relative the front case 2.1 by an assembly jig (not illustrated). In this state, the drive subassembly 1.2 may be assembled to the control subassembly 1.1. Subsequently, the assembly jig is removed and the needle shroud 7 translates in the distal direction D relative to the front case 2.1 under the force of the shroud spring 8 until the shroud rib 7.7 abuts the first plunger boss 10.1. The shroud beam 7.1 is prevented from deflecting radially outward by the stop 2.12 in the front case 2.1.

FIG. 15A is a longitudinal section of an exemplary embodiment of an autoinjector 1 according to certain aspects of the present invention after final assembly, and FIG. 15B is a schematic side view of an exemplary embodiment of an autoinjector 1 according to certain aspects of the present invention after final assembly, wherein the case 2 is removed for clarity.

In an exemplary embodiment, after the final assembly of the drive subassembly 1.2 to the control subassembly 1.1, the autoinjector 1 may be kept in temperature controlled environment (e.g., cold chain storage) to, for example, reduce creep in highly stressed components, e.g. under load from the drive spring 9.

An exemplary sequence of operation of an exemplary embodiment of the autoinjector 1 is as follows:

If applicable, the autoinjector 1 is removed from the packaging. The medicament in the syringe 3 may be visually inspected through a viewing window (not shown), which can be a transparent part of the case 2 or a cut-out in the case 2 aligned with the syringe 3.

The cap 11 is removed by pulling it in the distal direction D away from the case 2. As the cap 11 translates distally relative to the case 2, the bosses 11.2 on the cap 11 frictionally engage the protective needle sheath 5 and pull it off the needle 4 as the cap 11 is pulled in the distal direction D, and the compliant beam 11.3 disengages the aperture 7.6 in the needle shroud 7, as shown in FIG. 16. The compliant beam 11.3 translates distally within the aperture 7.6 until it is no longer abutted radially by the radial stop 2.15 and engages a proximal surface of the aperture 7.6 (which may be ramped) and deflects radially to disengage the aperture 7.6. The syringe 3 is fixed in position relative to the case 2, so pulling the cap 11 in the distal direction D does not cause any axial movement of the syringe 3. In an exemplary embodiment, the syringe 3 is also fixedly rotationally relative to the case 2 (e.g., by an interference fit with the case 2 and/or the needle shroud 7).

FIG. 17A is a longitudinal section of an exemplary embodiment of the autoinjector 1 according to certain aspects of the present invention prior to use. FIG. 17B is a schematic side view of an exemplary embodiment of the autoinjector 1 according to certain aspects of the present invention prior to use, wherein the case 2 is removed for clarity.

When the cap 11 is removed, the needle shroud 7 is in a first extended position FEP relative to the case 2, protruding from the case 2 in the distal direction D. The first extended position FEP is defined by the first plunger boss 10.1 abutting the shroud rib 7.7.

FIG. 18A is a longitudinal section of an exemplary embodiment of the autoinjector 1 according to certain aspects of the present invention during use. FIG. 18B is a schematic side view of an exemplary embodiment of the autoinjector 1 according to certain aspects of the present invention during use, wherein the case 2 is removed for clarity.

When the autoinjector 1 is pressed against an injection site, the needle shroud 7 translates proximally relative to the case 2 against the biasing force of the shroud spring 8 from the first extended position FEP to a retracted position RP, as shown in FIGS. 18A and 18B.

FIG. 19 shows an exemplary embodiment of the plunger release mechanism 12 when the needle shroud 7 is in the retracted position RP. As the needle shroud 7 translates from the first extended position FEP to the retracted position RP, the needle shroud 7 translates distally causing the first plunger boss 10.1 to, starting from the position shown in FIG. 8, ride along the shroud rib 7.7 until it is distal of the shroud rib 7.7. When the first plunger boss 10.1 is distal of the shroud rib 7.7, the plunger 10 is no longer prevented from rotating in the second rotational direction R2 relative to the case 2. Thus, the force of the drive spring 9 on the plunger 10 and the engagement of the second plunger boss 10.2 on the second angled surface 2.11 in the case slot 2.3, causes the plunger 10 to rotate relative to the case 2. In an exemplary embodiment, the needle shroud 7 may include an aperture, a recess or a slot proximal of the shroud rib 7.7 to accommodate the first plunger boss 10.1 when the needle shroud 7 is in the retracted position RP and the plunger 10 rotates relative to the case 2.

In an exemplary embodiment, the shroud rib 7.7 (e.g., on the longitudinal face 7.10) may include a resistance feature (e.g., a projection, a ramp, a recess, etc.) adapted to abut the first plunger boss 10.1 as the needle shroud 7 translates from the first extended position FEP to the retracted position RP. When the first plunger boss 10.1 abuts the resistance feature, a tactile feedback is provided in the form of increased resistance to pressing the autoinjector 1 against the injection site. The tactile feedback may be used to indicate that needle 4 will be inserted into the injection site upon further depression of the autoinjector 1 against the injection site. Prior to the needle shroud 7 reaching the retracted position RP, if the autoinjector 1 is removed from the injection site, the needle shroud and reposition as the needle shroud 7 will re-extend to its initial position under the force of the shroud spring 8. When the needle shroud 7 is in the retracted position RP, the needle 4 has been inserted into the injection site. Those of skill in the art will understand that a penetration depth of the needle 4 may be varied by, for example, limiting retraction of the needle shroud 7 relative to the case 2, modifying an axial position of the syringe 3 relative to the case 2, modifying a length of the needle 4, etc. Thus, the autoinjector 1 of the present invention may be used for subcutaneous, intra-dermal and/or intra-muscular injection.

FIG. 20A is a longitudinal section of an exemplary embodiment of the autoinjector 1 according to certain aspects of the present invention during use. FIG. 20B is a schematic side view of an exemplary embodiment of the autoinjector 1 according to certain aspects of the present invention during use, wherein the case 2 is removed for clarity.

When the plunger 10 has rotated a sufficient distance in the second rotational direction R2 such that the second plunger boss 10.2 disengages the case slot 2.3, the plunger 10 is free to translate axially, under the force of the drive spring 9, relative to the case 2 to push the stopper 6 to deliver the medicament M from the syringe 3 through the needle 4.

In an exemplary embodiment, disengagement of the first plunger boss 10.1 from the shroud rib 7.7 and/or the second plunger boss 10.2 from the case slot 2.3 may provide an audible feedback indicating that delivery of the medicament M has started. A viewing window in the case 2 may allow for a visual feedback that the plunger 10 is advancing within the syringe 3 for assessing the progress of displacement of the medicament M.

FIG. 21A is a longitudinal section of an exemplary embodiment of the autoinjector 1 according to certain aspects of the present invention after use. FIG. 21B is a schematic side view of an exemplary embodiment of the autoinjector 1 according to certain aspects of the present invention after use, wherein the case 2 is removed for clarity.

When the autoinjector 1 is removed from the injection site, the needle shroud 7 translates distally relative to the case 2 from the retracted position RP to a second extended position SEP under the biasing force of the shroud spring 8. In the second extended position SEP, the needle shroud 7 extends beyond a distal tip of the needle 4 and locks in an axial position relative to the case 2. The second extended position SEP prevents needle-stick injury and may also indicate that the autoinjector 1 has been used (because the needle shroud 7 cannot move proximally from the second extended position SEP). In an exemplary embodiment, in the second extended position SEP, the needle shroud 7 protrudes further, e.g. 2 mm, from the case 2 than in the first extended position FEP. The needle shroud 7 may include an indicia (e.g., a red ring, text, a graphic) on a portion which is visually accessible when the needle shroud 7 is in the second extended position SEP but not in the first extended position FEP. The indicia may indicate that the autoinjector 1 has been used.

FIG. 22 is a schematic view of an exemplary embodiment of the second shroud lock mechanism 15 according to certain aspects of the present invention. As the needle shroud 7 translates from the retracted position RP toward the second extended position SEP, the shroud beam 7.1 passes the stop 2.12 in the distal direction D and relaxes radially outwards which is possible as the cap 11 is no longer present. In the second extended position SEP, the needle shroud 7 cannot translate proximally relative to the case 2, because the shroud beam 7.1 abuts the stop 2.12. The needle shroud 7 is thus locked in the second extended position SEP. Extension of the needle shroud 7 distally beyond the second extended position SEP may be prevented by a shroud boss 7.2 on the needle shroud 7 that abuts a case boss 2.8 on the case 2 (see FIG. 1).

FIGS. 23A to 23 E are schematic views of another exemplary embodiment of a plunger release mechanism 12 of the autoinjector 1 according to certain aspects of the present invention. The plunger release mechanism 12 is arranged for preventing release of the plunger 10 prior to retraction of the needle shroud 7 relative to the case 2 and for releasing the plunger 10 once the needle shroud 7 is sufficiently retracted. In an exemplary embodiment, the plunger release mechanism 12 comprises the plunger 10, the rear case 2.2, and the needle shroud 7 interacting with each other. In an exemplary embodiment, the needle shroud 7 is limited to axial movement relative to the case 2, and the plunger 10 can translate axially and rotate relative to the case 2.

In an exemplary embodiment, the plunger 10 comprises a first plunger boss 10.1 adapted to engage a shroud rib 7.7 on the needle shroud 7 and a second plunger boss 10.2 adapted to engage a case slot 2.3 in the case 2, and a plunger rib 10.3 adapted to engage the shroud rib 7.7 on the needle shroud 7. In an exemplary embodiment, the shroud rib 7.7 comprises a proximal face 7.8 adapted to engage the plunger rib 10.3, and a distal face 7.9 adapted to engage the first plunger boss 10.1. In an exemplary embodiment, the case slot 2.3 comprises a first angled surface 2.9 adapted to apply a rotational force in a first rotational direction R1 to the second plunger boss 10.2, a wall 2.10 adapted to abut the second plunger boss 10.2 to limit rotation of the plunger 10 relative to the case 2 in the first rotational direction R1, and a transversal surface 2.16.

FIG. 23A is a schematic view of an exemplary embodiment of the plunger release mechanism 12 of the autoinjector 1 according to certain aspects of the present invention during assembly of the drive subassembly 1.2.

In an exemplary embodiment of an assembly process of the drive subassembly 1.2, the plunger 10 with the drive spring 9 is inserted into the rear case 2.2. When the second plunger boss 10.2 is axially aligned with the case slot 2.3, the plunger 10 is rotated in the first rotational direction R1 until the second plunger boss 10.2 is moved into the case slot 2.3 until it abuts the wall 2.10. In this position, the first angled surface 2.9 prevents the second plunger boss 10.2 from moving in the second rotational direction R2, and thus prevents the plunger 10 from rotating relative to the case 2.

After a syringe 3 (with the protective needle sheath 5 disposed on the needle 4) is inserted into the control assembly 1.1, the drive subassembly 1.2 is coupled to the control subassembly 1.1. In an exemplary embodiment, a pair of resilient beams 2.13 (shown in FIG. 1B) on the rear case 2.2 is adapted to snap into recesses 2.14 (shown in FIG. 3) in the front case 2.1 to lock the drive subassembly 1.2 to the control subassembly 1.1. FIG. 23B shows the drive assembly 1.2 being coupled to the control subassembly 1.1, wherein the needle shroud 7 translates proximally (e.g., by use of an assembly jig) causing the shroud rib 7.7 to abut the plunger rib 10.3. As shown in FIG. 23C, as the shroud rib 7.7 pushes plunger rib 10.3, the angle of the plunger rib 10.3 causes the plunger 10 to rotate relative to the case 2 in the second rotational direction R2, and the second plunger boss 10.2 rides along the first angled surface 2.9 onto the transversal surface 2.16.

As shown in FIG. 23D, when the needle shroud 7 is released (e.g., by removing the assembly jig), the needle shroud 7 translates in the distal direction D relative to the case 2 under the force of the shroud spring 8 until the shroud rib 7.7 abuts the first plunger boss 10.1. For example, the distal face 7.9 of the shroud rib 7.7 may abut the first plunger boss 10.1 and maintain the needle shroud 7 in an axial position relative to the case 2. The second plunger boss 10.2 is prevented from disengaging the case slot 2.3 as it abuts the transversal surface 2.16 in the distal direction D.

FIG. 23E shows an exemplary embodiment of the plunger release mechanism 12 when the needle shroud 7 is in the retracted position RP. As the needle shroud 7 translates from the first extended position FEP to the retracted position RP, the needle shroud 7 translates distally causing the shroud rib 7.7 to, starting from the position shown in FIG. 23D, ride along the plunger rib 10.3 thereby rotating the second plunger boss 10.2 in the second rotational direction R2 along the transversal surface 2.16 until the second plunger boss 10.2 disengages the case slot 2.3 thus releasing the plunger 10. Then, under the force of the drive spring 9, the plunger 10 translates axially relative to the case 2 to deliver the medicament M from the syringe 3. In this exemplary embodiment, a tactile feedback may be provided in the form of an increase in resistance when the needle shroud 7 abuts and pushes against the plunger rib 10.3. The tactile feedback may indicate that needle insertion is or will commence, or medicament delivery will be initiated, if the autoinjector 1 is pressed further against the injection site.

In an exemplary embodiment the transversal surface 2.16 could be replaced by or comprise a concave shape for preventing inadvertent release of the plunger 10.

In another exemplary embodiment, the plunger 10 may not have the first plunger boss 10.1, the plunger rib 10.3 may be disposed at different angle than as described above, and the case slot 2.3 may not be angled relative to a transverse axis of the case 2. In this exemplary embodiment, when the autoinjector 1 is assembled, the plunger 10 is maintained in axial position relative to the case 2, because the second plunger boss 10.2 engages the case slot 2.3. However, the case slot 2.3 may not impart any rotational force on the second plunger boss 10.2 (or, in another exemplary embodiment, the case slot 2.3 may be angled to impart a rotational force on the second plunger boss 10.2 in the first rotational direction R1 to ensure that the second plunger boss 10.2 does not disengage the case slot 2.3 inadvertently).

FIGS. 24A and 24B show different longitudinal sections of another exemplary embodiment of the autoinjector 1. The syringe, the needle and the protective needle sheath are not shown for clarity. The illustrated embodiment may be arranged basically corresponding to the preciously described embodiments. The following description therefore predominantly deals with the differences of the embodiment of FIGS. 24A and 24B to the previous ones. A cap 11 may be removably disposed at a distal end of the case 2. The cap 11 may include an element (e.g., a barb, a hook, a narrowed section, etc.) arranged to engage the protective needle sheath, the case 2 and/or a needle shroud 7 telescoped within the case 2. The illustrated cap 11 does not comprise grip features. However, the cap 11 of FIGS. 24A and 24B may likewise comprise the grip features of the previously described embodiments for facilitating removal of the cap 11 (e.g., by twisting and/or pulling the cap relative to the case 2).

In an exemplary embodiment, a plunger release mechanism may be arranged for preventing release of the plunger 10 prior to retraction of the needle shroud 7 relative to the case 2 and for releasing the plunger 10 once the needle shroud 7 is sufficiently retracted. The plunger release mechanism is not shown in FIGS. 24A and 24B for clarity. However, a plunger release mechanism 12 such as the ones illustrated in the previous figures may be applied in the embodiment of FIGS. 24A and 24B.

In an exemplary embodiment, a first shroud lock mechanism 14 is arranged to prevent retraction of the needle shroud 7 relative to the case 2 when the cap 11 is in place, thereby avoiding unintentional activation of the autoinjector 1 (e.g., if dropped, during shipping or packaging, etc.). The first shroud lock mechanism 14 may comprise one or more compliant beams 11.3 on the cap 11 and a respective number of apertures 7.6 in the needle shroud 7 adapted to receive each of the compliant beams 11.3. When the cap 11 is attached to the autoinjector 1, the compliant beams 11.3 abut a radial stop 2.15 on the case 2 which prevents the compliant beams 11.3 from disengaging the apertures 7.6. Other than in the previously described embodiments the apertures 7.6 do not permit a limited axial movement of the cap 11 relative to the shroud 7. When the cap 11 is attached to the autoinjector 1, axial movement of the cap 11 in the proximal direction P relative the case 2 is limited by the cap 11 abutting the case 2. When the cap 11 is pulled in the distal direction D relative to the case 2, the compliant beams 11.3 may abut an edge of the aperture 7.6 and deflect to disengage the aperture 7.6, allowing for removal of the cap 11 and the protective needle sheath attached thereto. In an exemplary embodiment, the compliant beams 11.3 and/or the apertures 7.6 may be ramped to reduce force necessary to disengage the compliant beams 11.3 from the apertures 7.6. The cap furthermore comprises at least one compliant case beam 11.6 adapted to engage in a respective number of apertures 2.16 in the case 2. When the cap 11 is pulled in the distal direction D relative to the case 2, the compliant case beams 11.6 may abut an edge of the aperture 2.16 and deflect to disengage the aperture 2.16, allowing for removal of the cap 11 and the protective needle sheath attached thereto. In an exemplary embodiment, the compliant case beams 11.6 and/or the apertures 2.16 may be ramped to reduce force necessary to disengage the compliant case beams 11.6 from the apertures 2.16.

A second shroud lock mechanism 15 is adapted to lock the needle shroud 7 in an axial position relative to the case 2 after the autoinjector 1 has been removed from the injection site. In an exemplary embodiment, the second shroud lock mechanism 15 comprises at least one compliant shroud beam 7.1 on the needle shroud 7 adapted to proximally abut a stop 2.12 on the case 2 after the autoinjector 1 has been removed from the injection site. The abutment of the shroud beam 7.1 on the stop 2.12 prevents translation of the needle shroud 7 in the proximal direction P relative to the case 2. In an exemplary embodiment the stop 2.12 may be arranged on a compliant beam 2.17 in the case 2 to facilitate the initial assembly of the shroud 7. In an exemplary embodiment the shroud 7 can be assembled without the syringe 3 present so that the beam 2.17 with the stop 2.12 can deflect radially in and allows the shroud beam 7.1 to pass. The syringe 3 is then inserted and subsequently inwardly supports the beam 2.17 preventing it from deflecting radially inward thus creating an immovable stop 2.12. This allows for dispensing with the function of the cap illustrated in FIGS. 12 to 14.

In an exemplary embodiment, the autoinjector 1 may be formed from at least two subassemblies, e.g., a control subassembly 1.1 and a drive subassembly 1.2 such as the one shown in FIG. 4 and described in the corresponding section above to allow for flexibility as to the time and location of manufacture of the subassemblies 1.1, 1.2 and final assembly with the syringe 3.

In an exemplary embodiment, the control subassembly 1.1 comprises the cap 11, the needle shroud 7, the shroud spring 8 and the front case 2.1. To assemble the control subassembly 1.1, the shroud spring 8 is inserted into the needle shroud 7, and the needle shroud 7 with the shroud spring 8 is inserted into the front case 2.1. The cap 11 is arranged over the distal end of the needle shroud 7 and engages both the needle shroud 7 and the case 2 by the compliant beams 11.3, 11.6 being engaged in the apertures 7.6, 2.16. The shroud spring 8 is thus in an at least slightly loaded state wherein the load is statically resolved between the case 2 and the shroud 7 which are coupled through the compliant beams 11.3, 11.6 on the cap 11. In an exemplary embodiment the force exerted by the shroud spring 8 in that state is in a range from 2 N to 10 N whereas a force required to remove the cap 11 is greater, e.g. up to 25 N due to the design of the compliant case beams 11.6. The compliant case beam 11.6 is thus designed to safely resolve the force from the shroud spring 8 and yet allow easy removal of the cap 11.

After a syringe with the protective needle sheath disposed on the needle (not illustrated) is inserted into the control assembly 1.1, the drive subassembly 1.2 is coupled to the control subassembly 1.1. In an exemplary embodiment, a pair of resilient beams (not illustrated but similar to the ones shown in FIG. 1B) on the rear case 2.2 is adapted to snap into recesses (not illustrated) in the front case 2.1 to lock the drive subassembly 1.2 to the control subassembly 1.1. As the drive assembly 1.2 is coupled to the control subassembly 1.1, the needle shroud 7 does not have to be translated proximally by use of an assembly jig as in the previously described embodiments.

Instead the shroud 7 is already in the correct position and the control spring 8 is in the at least slightly loaded state. Coupling the drive assembly 1.2 to the control subassembly 1.1 thus causes the shroud rib 7.7 to abut the plunger rib 10.3. As shown in FIG. 7, as the shroud rib 7.7 pushes plunger rib 10.3, the angle of the plunger rib 10.3 causes the plunger 10 to rotate relative to the case 2 in the second rotational direction R2, and the second plunger boss 10.2 rides along the first angled surface 2.9 onto the second angled surface 2.11. When the second plunger boss 10.2 is disposed on the second angled surface 2.11, the force of the drive spring 9 imparts a rotational force on the plunger 10 in the second rotational direction R2 due to the angle of the second angled surface 2.11.

In an exemplary embodiment, after the final assembly of the drive subassembly 1.2 to the control subassembly 1.1, the autoinjector 1 may be kept in temperature controlled environment (e.g., cold chain storage) to, for example, reduce creep in highly stressed components, e.g. under load from the drive spring 9 and shroud spring 8.

As shown in FIG. 8, when the needle shroud 7 is released (e.g., by a user pulling the cap 11 in the distal direction D thereby disengaging the compliant case beams 11.6 from the respective apertures 2.16 in the case 2 while the first compliant beams 11.3 remain engaged in the apertures 7.6 within the shroud 7), the needle shroud 7 translates in the distal direction D relative to the case 2 under the force of the shroud spring 8 until the shroud rib 7.7 abuts the first plunger boss 10.1. For example, the distal face 7.9 of the shroud rib 7.7 may abut the first plunger boss 10.1 and maintain the needle shroud 7 in an axial position relative to the case 2. The second plunger boss 10.2 is prevented from disengaging the case slot 2.3, because the shroud rib 7.7 prevents the plunger 10 from rotating in the second rotational direction R2 relative to the case 2. For example, the longitudinal face 7.10 of the shroud rib 7.7 abuts the first plunger boss 10.1 to prevent rotation of the plunger 10. In this configuration, movement of the needle shroud 7 in the proximal direction P relative to the case 2 is restricted, because the radial stop 2.15 prevents the compliant beam 11.3 from disengaging the aperture 7.6 and the rib 11.4 on the cap 11 proximally abuts the front case 2.1. The axial position of the shroud 7 defined by the distal face 7.9 and the first plunger boss 10.1 may be such that the shroud beam 7.1 does not travel distally beyond the stop 2.12 in the front case 2.1 in that state.

A further sequence of operation of the embodiment of the autoinjector 1 illustrated in FIGS. 24A and 24B may be corresponding to the sequence of operation described above for the embodiments shown in the previous figures.

The embodiment of FIGS. 24A and 24B allows for assembling the autoinjector 1 without having to manipulate the shroud 7. An assembly jig is therefore not required.

In an exemplary embodiment, a tamper strip (not shown) may be arranged between the cap 11 and the front case 2.1 when the control subassembly 1.1 is assembled. The tamper strip may be useful for quality assurance.

FIG. 25A is a schematic view of a distal end of an exemplary embodiment of an autoinjector 1 according to certain aspects of the present invention during assembly. The autoinjector 1 comprises a case 2 adapted to hold a medicament container, such as a syringe.

In an exemplary embodiment, a cap 11 may be removably disposed at a distal end of the case 2. The cap 11 may include an element (e.g., a barb, a hook, a narrowed section, etc.) arranged to engage the case 2, a needle shroud 7 telescoped within the case, and/or a protective needle sheath on the needle. The protective needle sheath may be rubber and/or plastic. In an exemplary embodiment, the protective needle sheath is a rigid needle shield (RNS) formed from a rubber interior adapted to engage the needle with a plastic exterior at least partially covering an outer portion of the rubber interior. The cap 11 may comprise grip features 11.5 for facilitating removal of the cap 11 (e.g., by twisting and/or pulling the cap 11 relative to the case 2). In an exemplary embodiment, the grip features 11.5 may include one or more ribs, ridges, projections, bumps, notches, textured surfaces, or an overmolded coating (rubber, elastic, etc.), etc.

In an exemplary embodiment, a shroud spring 8 is arranged to bias the needle shroud 7 distally toward an extended position relative to the case 2. During use, the device 1 is pressed against an injection site causing the needle shroud 7 to move proximally relative to the case 2 to a retracted position against the biasing force of the shroud spring 8.

In an exemplary embodiment, a sheath removal mechanism 13 is arranged to remove the protective needle sheath from the medicament container on removal of the cap 11 from the autoinjector 1. The sheath removal mechanism 13 may comprise one or more compliant sheath removal beams 11.7 on the cap 11 adapted to engage the protective needle sheath. Typically, the sheath removal beams 11.7 extend in a proximal direction P from a distal face 11.10 of the cap 11 or are part of an internal sleeve extending in the proximal direction P from a distal face 11.10 of the cap 11. The compliant sheath removal beams 11.7 comprise respective inward ledges 11.8. When the compliant sheath removal beams 11.7 are relaxed the ledges 11.8 provide a clearance between them smaller than a diameter of a protective needle sheath. In an exemplary embodiment an assembly tool may be inserted in an axial direction through an opening 11.11 in the distal face 11.10 of the cap 11. FIG. 25B is a schematic view of an exemplary embodiment of the cap 11. The opening 11.11 is shaped similar to a keyhole such that an assembly tool may be inserted off centre and engage between at least two of the sheath removal beams 11.7 without blocking the path for a protective needle sheath during insertion.

In another exemplary embodiment one or more lateral apertures 11.9 are arranged in a lateral area of the cap 11 to allow insertion of an assembling tool. Corresponding lateral apertures 2.6, 7.3 may likewise be arranged in the case 2 and the needle shroud 7 in such a manner that a set of lateral apertures 11.9, 2.6, 7.3 respectively aligns when the cap 11 is attached to the case 2.

The cap 11 is assembled to the autoinjector 1 by being moved in a proximal direction P relative to the needle shroud 7. When the cap 11 is being attached to the autoinjector 1, the sheath removal beams 11.7 are inserted into the needle shroud 7 which is sufficiently wide to allow this.

When the cap 11 is attached to the autoinjector 1, axial movement of the cap 11 in the proximal direction P relative the case 2 is limited by a rib 11.4 on the cap 11 abutting the case 2.

FIG. 26 is a schematic view of the distal end of the autoinjector 1 with the assembled cap 11 during insertion of a wedge shaped assembly tool 16 through the opening 11.11 in the distal face 11.10. The wedge shaped assembly tool 16 engages between two of the sheath removal beams 11.7 splaying them apart thereby deflecting them in a radial outward direction. This opens up the clearance defined by the inward ledges 11.8 to an extent allowing a protective needle sheath to pass through. In an exemplary embodiment the wedge shaped assembly tool 16 can also be arranged to displace the shroud 7 axially in the same motion enabling the engagement of the second shroud lock mechanism 15 and priming of the plunger release mechanism 12.

FIG. 27 is a schematic view of the distal end of the autoinjector 1 with the assembled cap 11 during assembly of a medicament container 3 with a protective needle sheath 5. The medicament container 3 may be a pre-filled medicament container and have a needle 4 arranged at a distal end. When the autoinjector 1 and/or the medicament container 3 are assembled, a protective needle sheath 5 may be removably coupled to the needle 4. The protective needle sheath 5 may be a rubber needle sheath or a rigid needle sheath (which is composed of rubber and a full or partial plastic shell). In other exemplary embodiments, the medicament container may be a cartridge which includes the medicament M and engages a removable needle (e.g., by threads, snaps, friction, etc.).

The medicament container 3 and the protective needle sheath 5 are inserted into the case 2 and pushed in the distal direction D. Due to the assembly tool 16 the clearance between the ledges 11.8 on the compliant sheath removal beams 11.7 is wide enough to allow insertion of the protective needle sheath 5. In an exemplary embodiment the case 2 may comprise an axial stop 2.5 limiting axial movement of the medicament container 3 within the case 2 in the distal direction D, e.g. by engaging a neck portion 3.1 of the medicament container 3.

FIG. 28 is a schematic view of the distal end of the autoinjector 1 with the assembled cap 11, medicament container 3 and protective needle sheath 5. The assembly tool 16 is removed from the opening 11.11 in the distal face 11.10 of the cap 11 such that the sheath removal beams 11.7 are no longer splayed apart. Due to their beam stiffness the sheath removal beams 11.7 relax radially inwards, the inward ledges 11.8 reduce the clearance between them and engage a proximal end 5.1 of the protective needle sheath 5 thus axially coupling the cap 11 to the protective needle sheath 5. In an exemplary embodiment the sheath removal beams 11.7 are moulded in an inward deflected position which ensures they are always in intimate contact with the protective needle sheath 5 once the tool is removed. The wedge shaped assembly tool 16 is designed so that the sheath removal beams 11.7 are not deformed so far as to plastically yield. The contact point between the protective needle sheath 5 and the sheath removal beams 11.7 is arranged to minimise the moment acting to open the sheath removal beams 11.7 as the protective needle sheath 5 is removed. Hence, gripping of the protective needle sheath 5 does not rely on radial compressive force exerted by the sheath removal beams 11.7 but on a force exerted to the cap 11 in the distal direction D relative to the case 2. In an exemplary embodiment of the wedge shaped assembly tool 16 may be arranged to splay the sheath removal beams 11.7 in a direction perpendicular to the direction of the force exerted to the cap 11 during cap removal.

When the cap 11 is pulled in the distal direction D relative to the case 2, the ledges 11.8 engaged to the proximal end 5.1 of the protective needle sheath 5 pull the protective needle sheath 5 off the medicament container 3.

In an exemplary embodiment, a force required to press the needle shroud 7 may be approximately 2-12 N. Likewise, the mechanism may work with a higher force.

In an exemplary embodiment, the syringe 3 used in the autoinjector 1 may be a syringe capable of containing approximately 1 mL of the medicament M. In another exemplary embodiment, the syringe 3 used in the autoinjector 1 may be a syringe capable of containing approximately 2 mL of the medicament M.

The autoinjector 1 according to certain aspects of the present invention may have an increased shelf-life compared to conventional autoinjectors, because, for example, only the plunger 10 is subjected to the relatively high force of the drive spring 9.

The autoinjector 1 according to certain aspects of the present invention may be used as a platform as the drive spring 9 can be changed to alter a force applied to the plunger 10, e.g., for delivering medicaments with different viscosities drugs or reconstituted medicaments, or changing a time required to inject a dose of the medicament.

The cap 11 is suitable for being applied with any kind of injection device or autoinjector.

The term “drug” or “medicament”, as used herein, means a pharmaceutical formulation containing at least one pharmaceutically active compound,

wherein in one embodiment the pharmaceutically active compound has a molecular weight up to 1500 Da and/or is a peptide, a protein, a polysaccharide, a vaccine, a DNA, a RNA, an enzyme, an antibody or a fragment thereof, a hormone or an oligonucleotide, or a mixture of the above-mentioned pharmaceutically active compound,

wherein in a further embodiment the pharmaceutically active compound is useful for the treatment and/or prophylaxis of diabetes mellitus or complications associated with diabetes mellitus such as diabetic retinopathy, thromboembolism disorders such as deep vein or pulmonary thromboembolism, acute coronary syndrome (ACS), angina, myocardial infarction, cancer, macular degeneration, inflammation, hay fever, atherosclerosis and/or rheumatoid arthritis,

wherein in a further embodiment the pharmaceutically active compound comprises at least one peptide for the treatment and/or prophylaxis of diabetes mellitus or complications associated with diabetes mellitus such as diabetic retinopathy,

wherein in a further embodiment the pharmaceutically active compound comprises at least one human insulin or a human insulin analogue or derivative, glucagon-like peptide (GLP-1) or an analogue or derivative thereof, or exendin-3 or exendin-4 or an analogue or derivative of exendin-3 or exendin-4.

Insulin analogues are for example Gly(A21), Arg(B31), Arg(B32) human insulin; Lys(B3), Glu(B29) human insulin; Lys(B28), Pro(B29) human insulin; Asp(B28) human insulin; human insulin, wherein proline in position B28 is replaced by Asp, Lys, Leu, Val or Ala and wherein in position B29 Lys may be replaced by Pro; Ala(B26) human insulin; Des(B28-630) human insulin; Des(B27) human insulin and Des(B30) human insulin.

Insulin derivates are for example B29-N-myristoyl-des(B30) human insulin; B29-N-palmitoyl-des(B30) human insulin; B29-N-myristoyl human insulin; B29-N-palmitoyl human insulin; B28-N-myristoyl LysB28ProB29 human insulin; B28-N-palmitoyl-LysB28ProB29 human insulin; B30-N-myristoyl-ThrB29LysB30 human insulin; B30-N-palmitoyl-ThrB29LysB30 human insulin; B29-N—(N-palmitoyl-Y-glutamyl)-des(B30) human insulin; B29-N—(N-lithocholyl-Y-glutamyl)-des(B30) human insulin; B29-N-(ω-carboxyheptadecanoyl)-des(B30) human insulin and B29-N-(ω-carboxyheptadecanoyl) human insulin.

Exendin-4 for example means Exendin-4(1-39), a peptide of the sequence H-His-Gly-Glu-Gly-Thr-Phe-Thr-Ser-Asp-Leu-Ser-Lys-Gln-Met-Glu-Glu-Glu-Ala-Val-Arg-Leu-Phe-Ile-Glu-Trp-Leu-Lys-Asn-Gly-Gly-Pro-Ser-Ser-Gly-Ala-Pro-Pro-Pro-Ser-NH2.

Exendin-4 derivatives are for example selected from the following list of compounds:

-   H-(Lys)4-des Pro36, des Pro37 Exendin-4(1-39)-NH2, -   H-(Lys)5-des Pro36, des Pro37 Exendin-4(1-39)-NH2, -   des Pro36 Exendin-4(1-39), -   des Pro36 [Asp28] Exendin-4(1-39), -   des Pro36 [IsoAsp28] Exendin-4(1-39), -   des Pro36 [Met(O)14, Asp28] Exendin-4(1-39), -   des Pro36 [Met(O)14, IsoAsp28] Exendin-4(1-39), -   des Pro36 [Trp(O2)25, Asp28] Exendin-4(1-39), -   des Pro36 [Trp(O2)25, IsoAsp28] Exendin-4(1-39), -   des Pro36 [Met(O)14 Trp(O2)25, Asp28] Exendin-4(1-39), -   des Pro36 [Met(O)14 Trp(O2)25, IsoAsp28] Exendin-4(1-39), or -   des Pro36 [Asp28] Exendin-4(1-39), -   des Pro36 [IsoAsp28] Exendin-4(1-39), -   des Pro36 [Met(O)14, Asp28] Exendin-4(1-39), -   des Pro36 [Met(O)14, IsoAsp28] Exendin-4(1-39), -   des Pro36 [Trp(O2)25, Asp28] Exendin-4(1-39), -   des Pro36 [Trp(O2)25, IsoAsp28] Exendin-4(1-39), -   des Pro36 [Met(O)14 Trp(O2)25, Asp28] Exendin-4(1-39), -   des Pro36 [Met(O)14 Trp(O2)25, IsoAsp28] Exendin-4(1-39), -   wherein the group -Lys6-NH2 may be bound to the C-terminus of the     Exendin-4 derivative; -   or an Exendin-4 derivative of the sequence -   des Pro36 Exendin-4(1-39)-Lys6-NH2 (AVE0010), -   H-(Lys)6-des Pro36 [Asp28] Exendin-4(1-39)-Lys6-NH2, -   des Asp28 Pro36, Pro37, Pro38Exendin-4(1-39)-NH2, -   H-(Lys)6-des Pro36, Pro38 [Asp28] Exendin-4(1-39)-NH2, -   H-Asn-(Glu)5des Pro36, Pro37, Pro38 [Asp28] Exendin-4(1-39)-NH2, -   des Pro36, Pro37, Pro38 [Asp28] Exendin-4(1-39)-(Lys)6-NH2, -   H-(Lys)6-des Pro36, Pro37, Pro38 [Asp28] Exendin-4(1-39)-(Lys)6-NH2, -   H-Asn-(Glu)5-des Pro36, Pro37, Pro38 [Asp28]     Exendin-4(1-39)-(Lys)6-NH2, -   H-(Lys)6-des Pro36 [Trp(O2)25, Asp28] Exendin-4(1-39)-Lys6-NH2, -   H-des Asp28 Pro36, Pro37, Pro38 [Trp(O2)25] Exendin-4(1-39)-NH2, -   H-(Lys)6-des Pro36, Pro37, Pro38 [Trp(O2)25, Asp28]     Exendin-4(1-39)-NH2, -   H-Asn-(Glu)5-des Pro36, Pro37, Pro38 [Trp(O2)25, Asp28]     Exendin-4(1-39)-NH2, -   des Pro36, Pro37, Pro38 [Trp(O2)25, Asp28]     Exendin-4(1-39)-(Lys)6-NH2, -   H-(Lys)6-des Pro36, Pro37, Pro38 [Trp(O2)25, Asp28]     Exendin-4(1-39)-(Lys)6-NH2, -   H-Asn-(Glu)5-des Pro36, Pro37, Pro38 [Trp(O2)25, Asp28]     Exendin-4(1-39)-(Lys)6-NH2, -   H-(Lys)6-des Pro36 [Met(O)14, Asp28] Exendin-4(1-39)-Lys6-NH2, -   des Met(O)14 Asp28 Pro36, Pro37, Pro38 Exendin-4(1-39)-NH2, -   H-(Lys)6-des Pro36, Pro37, Pro38 [Met(O)14, Asp28]     Exendin-4(1-39)-NH2, -   H-Asn-(Glu)5-des Pro36, Pro37, Pro38 [Met(O)14, Asp28]     Exendin-4(1-39)-NH2, -   des Pro36, Pro37, Pro38 [Met(O)14, Asp28]     Exendin-4(1-39)-(Lys)6-NH2, -   H-(Lys)6-des Pro36, Pro37, Pro38 [Met(O)14, Asp28]     Exendin-4(1-39)-(Lys)6-NH2, -   H-Asn-(Glu)5 des Pro36, Pro37, Pro38 [Met(O)14, Asp28]     Exendin-4(1-39)-(Lys)6-NH2, -   H-Lys6-des Pro36 [Met(O)14, Trp(O2)25, Asp28]     Exendin-4(1-39)-Lys6-NH2, -   H-des Asp28 Pro36, Pro37, Pro38 [Met(O)14, Trp(O2)25]     Exendin-4(1-39)-NH2, -   H-(Lys)6-des Pro36, Pro37, Pro38 [Met(O)14, Asp28]     Exendin-4(1-39)-NH2, -   H-Asn-(Glu)5-des Pro36, Pro37, Pro38 [Met(O)14, Trp(O2)25, Asp28]     Exendin-4(1-39)-NH2, -   des Pro36, Pro37, Pro38 [Met(O)14, Trp(O2)25, Asp28]     Exendin-4(1-39)-(Lys)6-NH2, -   H-(Lys)6-des Pro36, Pro37, Pro38 [Met(O)14, Trp(O2)25, Asp28]     Exendin-4(S1-39)-(Lys)6-NH2, -   H-Asn-(Glu)5-des Pro36, Pro37, Pro38 [Met(O)14, Trp(O2)25, Asp28]     Exendin-4(1-39)-(Lys)6-NH2,

or a pharmaceutically acceptable salt or solvate of any one of the afore-mentioned Exendin-4 derivative.

Hormones are for example hypophysis hormones or hypothalamus hormones or regulatory active peptides and their antagonists as listed in Rote Liste, ed. 2008, Chapter 50, such as Gonadotropine (Follitropin, Lutropin, Choriongonadotropin, Menotropin), Somatropine (Somatropin), Desmopressin, Terlipressin, Gonadorelin, Triptorelin, Leuprorelin, Buserelin, Nafarelin, Goserelin.

A polysaccharide is for example a glucosaminoglycane, a hyaluronic acid, a heparin, a low molecular weight heparin or an ultra low molecular weight heparin or a derivative thereof, or a sulphated, e.g. a poly-sulphated form of the above-mentioned polysaccharides, and/or a pharmaceutically acceptable salt thereof. An example of a pharmaceutically acceptable salt of a poly-sulphated low molecular weight heparin is enoxaparin sodium.

Antibodies are globular plasma proteins (˜150 kDa) that are also known as immunoglobulins which share a basic structure. As they have sugar chains added to amino acid residues, they are glycoproteins. The basic functional unit of each antibody is an immunoglobulin (Ig) monomer (containing only one Ig unit); secreted antibodies can also be dimeric with two Ig units as with IgA, tetrameric with four Ig units like teleost fish IgM, or pentameric with five Ig units, like mammalian IgM.

The Ig monomer is a “Y”-shaped molecule that consists of four polypeptide chains; two identical heavy chains and two identical light chains connected by disulfide bonds between cysteine residues. Each heavy chain is about 440 amino acids long; each light chain is about 220 amino acids long. Heavy and light chains each contain intrachain disulfide bonds which stabilize their folding. Each chain is composed of structural domains called Ig domains. These domains contain about 70-110 amino acids and are classified into different categories (for example, variable or V, and constant or C) according to their size and function. They have a characteristic immunoglobulin fold in which two β sheets create a “sandwich” shape, held together by interactions between conserved cysteines and other charged amino acids.

There are five types of mammalian Ig heavy chain denoted by α, δ, ε, γ, and μ. The type of heavy chain present defines the isotype of antibody; these chains are found in IgA, IgD, IgE, IgG, and IgM antibodies, respectively.

Distinct heavy chains differ in size and composition; α and γ contain approximately 450 amino acids and δ approximately 500 amino acids, while μ and ε have approximately 550 amino acids. Each heavy chain has two regions, the constant region (C_(H)) and the variable region (V_(H)). In one species, the constant region is essentially identical in all antibodies of the same isotype, but differs in antibodies of different isotypes. Heavy chains γ, α and δ have a constant region composed of three tandem Ig domains, and a hinge region for added flexibility; heavy chains μ and ε have a constant region composed of four immunoglobulin domains. The variable region of the heavy chain differs in antibodies produced by different B cells, but is the same for all antibodies produced by a single B cell or B cell clone. The variable region of each heavy chain is approximately 110 amino acids long and is composed of a single Ig domain.

In mammals, there are two types of immunoglobulin light chain denoted by λ and κ. A light chain has two successive domains: one constant domain (CL) and one variable domain (VL). The approximate length of a light chain is 211 to 217 amino acids. Each antibody contains two light chains that are always identical; only one type of light chain, κ or λ, is present per antibody in mammals.

Although the general structure of all antibodies is very similar, the unique property of a given antibody is determined by the variable (V) regions, as detailed above. More specifically, variable loops, three each the light (VL) and three on the heavy (VH) chain, are responsible for binding to the antigen, i.e. for its antigen specificity. These loops are referred to as the Complementarity Determining Regions (CDRs). Because CDRs from both VH and VL domains contribute to the antigen-binding site, it is the combination of the heavy and the light chains, and not either alone, that determines the final antigen specificity.

An “antibody fragment” contains at least one antigen binding fragment as defined above, and exhibits essentially the same function and specificity as the complete antibody of which the fragment is derived from. Limited proteolytic digestion with papain cleaves the Ig prototype into three fragments. Two identical amino terminal fragments, each containing one entire L chain and about half an H chain, are the antigen binding fragments (Fab). The third fragment, similar in size but containing the carboxyl terminal half of both heavy chains with their interchain disulfide bond, is the crystalizable fragment (Fc). The Fc contains carbohydrates, complement-binding, and FcR-binding sites. Limited pepsin digestion yields a single F(ab′)2 fragment containing both Fab pieces and the hinge region, including the H—H interchain disulfide bond. F(ab′)2 is divalent for antigen binding. The disulfide bond of F(ab′)2 may be cleaved in order to obtain Fab′. Moreover, the variable regions of the heavy and light chains can be fused together to form a single chain variable fragment (scFv).

Pharmaceutically acceptable salts are for example acid addition salts and basic salts. Acid addition salts are e.g. HCl or HBr salts. Basic salts are e.g. salts having a cation selected from alkali or alkaline, e.g. Na+, or K+, or Ca2+, or an ammonium ion N+(R1)(R2)(R3)(R4), wherein R1 to R4 independently of each other mean: hydrogen, an optionally substituted C1-C6-alkyl group, an optionally substituted C2-C6-alkenyl group, an optionally substituted C6-C10-aryl group, or an optionally substituted C6-C10-heteroaryl group. Further examples of pharmaceutically acceptable salts are described in “Remington's Pharmaceutical Sciences” 17. ed. Alfonso R. Gennaro (Ed.), Mark Publishing Company, Easton, Pa., U.S.A., 1985 and in Encyclopedia of Pharmaceutical Technology.

Pharmaceutically acceptable solvates are for example hydrates.

Those of skill in the art will understand that modifications (additions and/or removals) of various components of the apparatuses, methods and/or systems and embodiments described herein may be made without departing from the full scope and spirit of the present invention, which encompass such modifications and any and all equivalents thereof. 

The invention claimed is:
 1. An autoinjector comprising: a case adapted to hold a medicament container having a needle; a needle shroud telescopically coupled to the case and movable between a first extended position relative to the case in which the needle is covered and a retracted position relative to the case in which the needle is exposed; a shroud spring biasing the needle shroud in a distal direction relative to the case; a plunger rotationally and slidably disposed in the case, the plunger rotatable relative to the case between a first rotational position in which the plunger is engaged to the case and a second rotational position in which the plunger is disengaged from the case, wherein the needle shroud is adapted to directly engage the plunger to rotate the plunger from the first rotational position to the second rotational position when the needle shroud translates from the first extended position to the retracted position; and a cap removably coupled to the case, wherein the cap includes a compliant beam adapted to releasably engage an aperture in the case in a manner such that the compliant beam disengages from the aperture in the case and no longer radially abuts the case when the cap is moved a distance in the distal direction relative to the case, wherein the cap is configured such that a force required to disengage the compliant beam from the aperture is greater than a force exerted on the needle shroud by the shroud spring when the compliant beam is engaged to the aperture.
 2. The autoinjector according to claim 1, wherein the needle shroud is movable to a second extended position relative to the case in which the needle is covered and the needle shroud is inhibited from translating relative to the case.
 3. The autoinjector according to claim 1, wherein the plunger is configured to translate relative to the case under force of a drive spring when the plunger is in the second rotational position and the needle shroud is in the retracted position.
 4. The autoinjector according to claim 1, wherein the needle shroud includes a compliant beam radially abutting the case when the needle shroud is in the first extended position and the retracted position, wherein the compliant beam of the needle shroud is configured to deflect radially when the needle shroud is in a second extended position in which the needle shroud axially abuts the case.
 5. The autoinjector according to claim 1, wherein the plunger includes a first plunger boss adapted to engage a shroud rib disposed on the needle shroud, and a second plunger boss adapted to engage a case slot in the case.
 6. The autoinjector according to claim 5, wherein, when the plunger is in the first rotational position and the needle shroud is in the first extended position, the first plunger boss engages the shroud rib and the second plunger boss engages the case slot.
 7. The autoinjector according to claim 6, wherein, when the needle shroud is in the retracted position, the plunger rotates from the first rotational position to the second rotational position and disengages the case slot.
 8. The autoinjector according to claim 1, wherein the plunger includes a plunger boss adapted to engage a case slot in the case, and a plunger rib adapted to engage a shroud rib disposed on the needle shroud.
 9. The autoinjector according to claim 8, wherein, when the plunger is in the first rotational position and the needle shroud is in the first extended position, the plunger boss engages the case slot.
 10. The autoinjector according to claim 9, wherein, when the needle shroud translates from the first extended position to the retracted position, the needle shroud abuts the plunger rib to rotate the plunger relative to the case from the first rotational position to a second rotational position to disengage the plunger boss from the case slot.
 11. The autoinjector according to claim 1, wherein the cap comprises: a distal face; another compliant beam extending in a proximal direction from the distal face and defining a space for receiving a protective needle sheath, the other compliant beam including a ledge adapted to engage the protective needle sheath, wherein the other compliant beam is configured to engage the protective needle sheath when the other compliant beam is approximately perpendicular to the distal face in a first position, and receive the protective needle sheath when the other compliant beam is at an angle to the distal face in a second position.
 12. The autoinjector according to claim 11, wherein the other compliant beam is biased toward the first position.
 13. The autoinjector according to claim 11, wherein the ledge is adapted to engage proximally behind a proximal end of the protective needle sheath or into a recess within the protective needle sheath.
 14. The autoinjector according to claim 11, further comprising one or more openings in a distal face of the cap or one or more lateral apertures arranged in a lateral area of the cap to allow insertion of an assembling tool for applying a force to move the other compliant beam from the first position to the second position.
 15. A shroud lock mechanism comprising: a cap adapted to be removably coupled to a case of an injection device; a needle shroud telescopically coupled to the case and movable between a first extended position relative to the case in which a needle of the injection device is covered and a retracted position relative to the case in which the needle is exposed, the needle shroud adapted to directly engage a plunger of the injection device to rotate the plunger from a first rotational position to a second rotational position when the needle shroud translates from a first extended position to a retracted position; and a compliant beam extending from a portion of the cap, the compliant beam adapted to releasably engage an aperture in the case such that the compliant beam disengages from the aperture and no longer radially abuts the case of the injection device when the cap is moved a distance in a distal direction relative to the case of the injection device, wherein the compliant beam is configured such that a force required to disengage the compliant beam from the aperture in the case is greater than a force exerted on the needle shroud by a shroud spring when the compliant beam is engaged in the aperture in the case.
 16. The shroud lock mechanism according to claim 15, wherein the cap further comprises another compliant beam, the other compliant beam adapted to releasably engage an aperture in the needle shroud of the injection device such that the needle shroud translates in the distal direction when the cap is moved in the distal direction relative to the case of the injection device. 